In brief, a fluid lens comprises an interface between two fluids having dissimilar optical indices. The shape of the interface can be changed by the application of external forces so that light passing across the interface can be directed to propagate in desired directions. As a result, the optical characteristics of a fluid lens, such as whether the lens operates as a diverging lens or as a converging lens, and its focal length, can be changed in response to the applied forces.
Fluid lens technology that employs electrical signals to control the operation of the fluid lens has been described variously in U.S. Pat. No. 2,062,468 to Matz, U.S. Pat. No. 6,399,954 to Berge et al., U.S. Pat. No. 6,449,081 to Onuki et al., U.S. Pat. No. 6,702,483 to Tsuboi et al., and U.S. Pat. No. 6,806,988 to Onuki et al., in U.S. Patent Application Publication Nos. 2004/0218283 by Nagaoka et al., 2004/0228003 by Takeyama et al., and 2005/0002113 by Berge, as well as in several international patent documents including WO 99/18456, WO 00/58763 and WO 03/069380.
Additional methods of controlling the operation of fluid lenses include the use of liquid crystal material (U.S. Pat. No. 6,437,925 to Nishioka), the application of pressure (U.S. Pat. No. 6,081,388 to Widl), the use of elastomeric materials in reconfigurable lenses (U.S. Pat. No. 4,514,048 to Rogers), the uses of micro-electromechanical systems (also known by the acronym “MEMS”) (U.S. Pat. No. 6,747,806 to Gelbart), the use of stack-type piezoelectric actuators to vary the focus of the lens member to compensate for temperature fluctuations (U.S. Pat. No. 6,188,526 to Sasaya et al.), the use of piezoelectric material to deform a variable focus lens (Japanese Patent No. JP2002243918), and the use of piezoelectric element in contact with a fluid such that the element changes dimensions in response to changes in voltage, changing the fluid pressure and altering the radius of curvature of an associated transparent membrane (GB Patent 1,327,503); the disclosures of the foregoing are hereby incorporated in their entireties herein.
There is a need for improved systems and methods for using fluid lenses in present day systems.
In the drawings, while every effort has been made to use like numerals to indicate like parts throughout the various views, the right is reserved to make corrections should errors become apparent.